8 research outputs found

    Raman spectroscopy applied to understanding Prehistoric Obsidian Trade in the Pacific Region

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    Obsidian is a natural volcanic glass which is amorphous and isotropic. These characteristics allow it to be easily shaped as little force is required to produce conchoidal fractures of predictable forms and sizes. A class of obsidian artefacts known as 'stemmed tools' have been found in locations situated across lowland Papua New Guinea and have been approximately dated to the early and middle Holocene periods (c. 10 000-3400 BP). The fragile nature of these tools, and their rarity, mean that non-destructive techniques are highly desirable for chemical analysis. In this study Raman spectroscopy was used, in conjunction with multivariate analysis, to discriminate between the major geological sources of obsidian within the Pacific Region. Application of principle component analysis (PCA) to data collected from forty-three samples from three major geological sources revealed the presence of three distinct clusters. In addition, Raman spectra were collected from an obsidian stemmed tool housed at the Pitt Rivers Museum at the University of Oxford, United Kingdom. The locality of the stemmed tool was tentatively assigned to the New Britain obsidian source group. The results are helpful for tracking social interaction during an early period of Pacific Prehistory. Crow

    A Survey of Empirical Results on Program Slicing

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    International audienceBACKGROUND:Patients with peripheral artery disease have an increased risk of cardiovascular morbidity and mortality. Antiplatelet agents are widely used to reduce these complications.METHODS:This was a multicentre, double-blind, randomised placebo-controlled trial for which patients were recruited at 602 hospitals, clinics, or community practices from 33 countries across six continents. Eligible patients had a history of peripheral artery disease of the lower extremities (previous peripheral bypass surgery or angioplasty, limb or foot amputation, intermittent claudication with objective evidence of peripheral artery disease), of the carotid arteries (previous carotid artery revascularisation or asymptomatic carotid artery stenosis of at least 50%), or coronary artery disease with an ankle-brachial index of less than 0路90. After a 30-day run-in period, patients were randomly assigned (1:1:1) to receive oral rivaroxaban (2路5 mg twice a day) plus aspirin (100 mg once a day), rivaroxaban twice a day (5 mg with aspirin placebo once a day), or to aspirin once a day (100 mg and rivaroxaban placebo twice a day). Randomisation was computer generated. Each treatment group was double dummy, and the patient, investigators, and central study staff were masked to treatment allocation. The primary outcome was cardiovascular death, myocardial infarction or stroke; the primary peripheral artery disease outcome was major adverse limb events including major amputation. This trial is registered with ClinicalTrials.gov, number NCT01776424, and is closed to new participants.FINDINGS:Between March 12, 2013, and May 10, 2016, we enrolled 7470 patients with peripheral artery disease from 558 centres. The combination of rivaroxaban plus aspirin compared with aspirin alone reduced the composite endpoint of cardiovascular death, myocardial infarction, or stroke (126 [5%] of 2492 vs 174 [7%] of 2504; hazard ratio [HR] 0路72, 95% CI 0路57-0路90, p=0路0047), and major adverse limb events including major amputation (32 [1%] vs 60 [2%]; HR 0路54 95% CI 0路35-0路82, p=0路0037). Rivaroxaban 5 mg twice a day compared with aspirin alone did not significantly reduce the composite endpoint (149 [6%] of 2474 vs 174 [7%] of 2504; HR 0路86, 95% CI 0路69-1路08, p=0路19), but reduced major adverse limb events including major amputation (40 [2%] vs 60 [2%]; HR 0路67, 95% CI 0路45-1路00, p=0路05). The median duration of treatment was 21 months. The use of the rivaroxaban plus aspirin combination increased major bleeding compared with the aspirin alone group (77 [3%] of 2492 vs 48 [2%] of 2504; HR 1路61, 95% CI 1路12-2路31, p=0路0089), which was mainly gastrointestinal. Similarly, major bleeding occurred in 79 (3%) of 2474 patients with rivaroxaban 5 mg, and in 48 (2%) of 2504 in the aspirin alone group (HR 1路68, 95% CI 1路17-2路40; p=0路0043).INTERPRETATION:Low-dose rivaroxaban taken twice a day plus aspirin once a day reduced major adverse cardiovascular and limb events when compared with aspirin alone. Although major bleeding was increased, fatal or critical organ bleeding was not. This combination therapy represents an important advance in the management of patients with peripheral artery disease. Rivaroxaban alone did not significantly reduce major adverse cardiovascular events compared with asprin alone, but reduced major adverse limb events and increased major bleeding
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